Regenerative heat exchanger



Jn 30, 1942. Q K, W BQESTAD v 2,287,777'.

REGENERATIVE HEAT EXGHANGER V 2 Sheets-Sheet l original Filed Jan.l22, 19?:

TTQRNEY.

June 3o, 1942;

G. K. W. BOESTAD REGENERATIYVE HEATEXCHANGER Original-Fil-ved'Jan. 22, 193'? 2 Sheets-Sheet 2 .EN A 00 Y@ M 7% f @N L.

a 9) i 7 0,- @mi 1.

Patented June 30, 1942 2,287,777 v REGENERATIVE naar Excnaucaa Gustav Karl William Boestad, Lidfngo, Sweden,

lassigncxbygmesne assignments, to J Leslie M. Merrill and Percy 1I. Batten,

' Mai-ble,

trustees arvisC.

original applicati@ January 22, 1937, serial. Nc. 121,890. Divided and this application October 5, 1939, Serial Nc. 298,047. In Ge January 23,1936

A'1 claims.

application Serial No. 121,890, led January 22, 1937, which lhas become -Patent No. 2,229,691, issued January 28,1941. l

The present invention relates to regenerative heat exchangers, and has particular reference to regenerative heat exchangersof the kind in which a body of `heat exchange materialwhich is preferablyv of multiple plate form is arranged to rotate ina stationary casing having head plates at each end to which the conduits are connected for iiow of the media, such as air and combustion gases, between which heat is to be exchanged.

In heat exchangers of the above kind, packings are provided between the rotary portion of the apparatus and the casing and falso between thei two compartments of y the apparatus through which the, different media ilow, the object'of these packings .being to preventshort circuiting of either of the media from the inlet to the outlet side' of the apparatus without passing throughv the body of heat exchanging material, and also to prevent as far as possible a direct connection between the different passages in which the two media are intended vto iiow.

Effective sealing of theV character desired has,

however, proved to be difcult in apparatus of this kind,'particularly in large units, because of the relative movement of parts due to expansion and contraction under the influence of the different degrees of heat to which derent parts of the apparatus are subjected.

This application is a division of my co-pending heat exchange apparatus embodying the invention;

Fig. 2 is a plan view on a reduced scale taken on the line 2-2 of Fig. 1;

Fig. 3 is an enlarged detail of part of the structure shown in Fig. 1;

Fig. 4 is a fragmentary side view on an enlarged scale of sealing structure embodied in the apparatus shown in Fig. 1;

Fig. 5 is ,a section taken on the line' 5--5 of Fig. 6 is a view similar to Fig. 4 butshowing the parts in a different relationship; and

Fig. '7 is a section taken on theline 1-1 of Fig. 6. v

Referring now more particularly toFigs. 1 to 3, the heat exchanger illustrated is of a well known type and comprises a rotor indicated generally at 2 which is divided by means of cylindrical partitions I and radial partitions 6 into a number of segment-shaped compartments lled with heat exchanging material 8 which is advantal geously in the form of corrugated plates providing between them a relatively large number of longitudinally extending passages of small crosssectional area.

On the hotter end of the heat exchange structure the space in the rotor for ow of the iluid The diiliculty of obtaining satisfactory sealing has been such that heretofore leakage `losses of the order of four percent have had to be taken into consideration in even the most favorable cases.

The present invention has for its principal object the improvement of heat exchange structure of the kind under consideration in a manner enablingleakage losses'of the kind described to be materially reduced. More particularly, the invention has for its primary object the improvement of certain portions of the rotor structure which cooperate with the head plate structure of the apparatus to provide the seals between differentcompartments of the apparatus as will hereinafter more fully appear in conjunction with the following description of a preferred form of apparatus embodying the invention.

In the drawings forming a part of this specification and illustrative'of this apparatus:

media is advantageously further divided by means of'additlonal cylindrical partitions I0.

The rotor 2 is provided with a central vertical shaft I2 mounted in bearings Il and I6 at the upper and lower ends of the structure respectively, which shaft is driven through the mediumr of suitable bevel gearing indicated at i8. -The weight of the rotor is supported by the beams 4 20 and 22 to which the'weight is transmitted through bearing I4.

.Around the rotor 2 and radically spaced therefrom is the cylindrical stationary outer casing 24, this casing being heat insulated from the rotor by means of the circumferential belt of insulating material 26 carried by the rotor. The feature of providing the insulating material on the outer wall of the rotor rather than on they casingv structure forms. per se, no part of the present invention and constitutes a portion of the claimed subject matter of my aforesaid application Serial No. 121,890, of which this is a division. At its upper and lower ends the casing I3 is provided with annular flanges 28 and 30, respectively.

The stationary head plates 32 and 34 are connected to the conduits for the fiowof the media Fig. 1 is a side elevation, partly in section, of 55 between which' heat is to be exchanged. Plates 32 and 34 are respectively united with' plates 38 and 38, the latter being rigidly connected as at 48 and 42 to the central portion of the stationary casing structure.

Plates 32, 34, 36, and 38 are provided in known manner with suitable openings for iiow therethrough of heat exchange media, the openings through plates 32 and 36 being indicated at 44 and 48` in Fig. 2.

If, for example, the exchanger is used as a preheater for combustion air, the hot combustion gases ilow through the side of the heat exchanger at the left of Fig. 1 in the direction of the arrows 48 and 50, owing out through the opening 44 in the plates 32 and 38 after having owed into the exchanger through a like opening (not shown) in the bottom plates 34 and 38. The air to be heated ows through the right side of the preheater as viewed in Fig. 1, preferably in counter-current direction as indicated by the arrows 52 and 54, passing through the opening 46 in the upper head-plate structure and through a like opening (not shown) in the bottom head plate structure.

. Since the head plates 32 and 34 are contacted by the hot combustion gases, they are subjected to4 longitudinal expansion and contraction because of temperature variations. l

In order that such expansion and contraction shall be in radial direction only and shall not affect the clearances in the structure, a novel construction is employed in accordance with the invention which is illustrated on a larger scale in Fig. 3. As shown in this ligure, the head plate 32 is resiliently secured so as to have relative radial movement at its periphery with respect to the ring flange 28 on the casing I3. Plate 32 is provided with radially oblong apertures 56 and the plate is held against the upper surface of the flange 28 in light contact therewith through the medium of a series of bolts 58 passing through these apertures and suitable bolt holes in the flange 28, such bolts having associated therewith springs 60 located between the retainers 62 and 64. The proper tension on the springs is secured by suitable adjustment of the nuts 66.

As will be evident from Fig. 1, the lower head plate 34 is similarly secured to the lower flange ring 38 by means of bolts 68 and springs 18.

The above described head plate construction also forms a portion of the claimed subject matter of my aforesaid application Serial No. 121,890.

.As indicated in Fig. 1, circumferential packing members 12 and 14 are arranged at the upper and lower ends respectively of the rotor to prevent ilow of the gaseous media through the space between the outer wall of the rotor and the casing wall I3.

The radially extending packing members, indicated generally at 16 and 18 in Fig. 1, at the upper and lower ends of the radial partitions respectively, contact the diametral webs of the upper and lower head plate structures as the rotor revolves (the diametral web of the upper head plate structure being shown at 80 in Fig. 2). When these packing members pass in contact with the webs they serve to separate the passage for flow of one heat exchange medium on one side of the apparatus from the passage for flow of the other heat-exchange medium on the other side of the apparatus.

In Figs. 4 to 'I there 'is shown in detail the improved construction according to the present invention for insuring proper sealing contact between the packing members and the head plate structure. In these views, which illustrate the bottom packing member 18, the thin packing strips of sheet metal or the like are indicated at 82. These packing strips instead of being secured directly to the partitions 6, as is usually the case, are carried by radially extending arms 84 which at their inner ends are rigidly secured to the hub portion 88 of the rotor 2.

The partitions 8 are provided with a series of vertical slots 88 having open ends and bolts 88 pass through these slots and through suitable bolt holes 92 in the arms 84. Springs 94. are located under the heads of bolts 88 so that the bolts, through the action of these springs, serve to resiliently hold the arms 84 against the partition plates E.

From a consideration of Fig. 1 it will be evident that the lower portion of the rotor structure is subjected to greater expansion than the upper portion. 'I'his is due to the fact that the combustion gases enter the lower portion at higher temperature than they leave the upper wrtion andthe air leaves the lower portion at a higher temperature than it enters the upper portion. Due to-this difference in temperature and to the consequent uneven expansion, the rotor structure may in effect be warped by expansion from a condition such as shown in Fig. 4, where the rotor is assumed to be in cold state, to a condition such as shown in Fig. 6 where the rotor is assumed to be in a hot state.

If the radial packing members were rigidly -attached to the radial partitions, it is evident that at their outer ends they would be pulled away from proper contact with the head plate structures, but because of the rigid attachment of these packing members to the h ub portion of the rotor, and the yielding slotted connection between the packing members and the partitions,

the packing members may and do retain their original and' proper position, which provides an eifective seal between the radial partitions and the head plate structures.

Obviously the details of construction may be altered without departing 'from the spirit or scope of the invention as defined in the appended claims.

What is claimed is:

1. In a regenerative heat exchanger, a rotor having a series of radially extending partitions and packing members secured to the ends of said partitions, said packing members being rigidly secured at their inner ends relative to said parl titions and being vieldingly connected to the partitions to permit relative movement of the pack- 'ingly connected to the end portions of the partitions so as to permit relative movement of the radially outer'portions of said packing members with respect to raid partitions in the planes of the partitions.

3. In a regenerative heat exchanger, a rotor having a hub portion and a series of partitions extending radially from said hub portion, packing members at the ends of said partitions, said packing members being rigidly secured to the hub portion of the rotor and means comprising bolts and springs for connecting said packing i members to the end portions of said partitions so as to permit' relative movement between the packing members andthe partitions in the planes of the partitions.

4. A regenerative heat exchanger including a rotor having partitions extending in generally radial direction, a stationarycasing structure including head plate structures atthe ends thereof, and packing members adapted to provide a seal between said head plate structure and said. partitions in certain positions of the rotor, the radial inner portions of said packing members being rigidly secured to the rotor structure inner ends to the hub portion of the rotor and having substantially free `movement at their outer ends relative' to said partitions.

6. A regenerative heat exchanger including a rotor having a hub and partitions extending outwardly from said hub, a stationary casing structure including head plate structures at the ends i thereof, packing members adapted to provide a seal between said' head plate structures and said radial partitions in certain positions of the rotor, said packing members comprising arms extending outwardly from said hub and having their inner portions fixed to the rotor structure along only a small portion of the length of-the arms, whereby t0 permit relative movement between the rotor and the major portion of the length oi the arms, and packing strips fixed to said arms and arranged to substantially contact said head plate structures in said certain positions of the rotor, and means providing a yielding connection 4between said partitions and the relatively movable portions of said arms.

7. A regenerative heat exchanger including a 4rotor having a hub .and a plurality of partitions extending outwardly therefrom, a stationary casing structure including head plate structures at the ends thereof, packing members comprising arms extending outwardly from said hub adjacent to the ends of said partitions and rigidly xed tothe rotor structure at their radially inner ends, the outer portions of said arms having relative movement in axial direction with respect to said partitions, yielding means for connecting the relatively movable portions of said arms to said partitions, and packing strips carried by said arms for providingfa seal between said head plate structures and said arms in certain positions of the rotor to divide the interior of the casing into diierent paths of flow for different iluid media.

G'USTAV CARL WILLIAM BOESTAD. 

